Despite the use of sophisticated safety systems including centrally controlled safety systems, train accidents continue to occur. These sometimes occur as a result of local failures in the centrally controlled safety systems. In February 2016, two commuter trains in southern Germany collided head-on in good weather resulting in at least ten dead. In the same year, a similar head-on collision between two trains occurred in Ruvo di Puglia and Corato, Italy causing twenty deaths and dozens injured. On 9 Oct. 2016, 33 people were injured in a collision of trains near New Hyde Park on Long Island when a track maintenance train, moving on an adjacent track entered the track space of a commuter train.
The first two train collisions mentioned above happened on single train-track two way traffic areas, despite both railways deploying high-tech train braking systems to prevent such collisions.
CN1325805 addresses the problem of calculating the separation distances of trains on a track. The problem addressed by CN1325805 is to detect the present on the same track of two trains travelling in opposite directions, i.e. travelling towards each other, to enable emergency braking systems to be activated to avoid a head-on collision. To achieve this, each train is provided with a single transponder which emits a track-related or track-specific frequency. The purpose therefore is to enable any train receiving the track-specific frequency to determine if the track identified by the track-specific frequency is the same track as it itself is travelling on which warns of a potential collision. However, CN1325805 does not include calculating actual distances between trains and does not suggest enabling any transponder on any train to respond with a reply signal when it receives a transponder signal from another train.
CN102756747 discloses a system which uses sound wave technology to calculate a target train distance. A first train sends out a radio signal and a sound wave. A target train (second train) receives the radio signal and starts counting the time lapse to receiving the sound wave sent from the first train. On receiving the sound wave sent from the first train, the time lapse counter stops and the elapsed time value is used with the speed of sound to determine the distance between the two trains.
CN1124858 discloses an on-board radio device which transmits its own identification code, own position (assumed to be latitude and longitude), speed, heading and track to other receivers. An on-board receiver receiving the above data plots the position on a computer display.
JP2011010515 discloses a radio communication device which performs radio communication between both trains, and a movement blocking controller on which a relative movement safety system is mounted. To always keep a critical stop point of the following train in front of that of the preceding train, the preceding train transmits its own critical stop point to the following train. On receipt of the critical stop point, the movement blocking controller of the following train generates a speed limit pattern for its own train based on the critical stop point received. Otherwise, the preceding train unilaterally generates a speed limit pattern for the following train based on its own critical stop point or a speed limit command, and transmits it to the following train.
CN103171596 discloses a safety system for a train which depends on the travelling direction. On a same travelling direction, a second train will continuously transmit a “Forward Characteristic” pulse string and wait for the first train to send back a “Backward Characteristic” pulse string. A separation distance is determined from the total time between these two pulse strings multiplied by the radio wave speed and divided by two. The system is designed for head to tail train collisions as the system uses the same frequency for trains travelling in the same direction. It cannot detect trains travelling in opposite directions, i.e. head to head, on the same track as both trains' systems operate in different frequencies.
There is a need for a system to provide train drivers with at least a traffic situation display with alerts and warnings to allow drivers to make local decisions to prevent collisions, especially head-on collisions.